Sterilization-protecting agent and sterilization method

Abstract

A material comprising a biologically active substance (or ligand) to be sterilized, including proteins (e.g., antibodies and enzymes), peptides, DNA, RNA, and glycoproteins, with or without a carrier, and sterilization-protecting agent comprising a trisaccharide or higher saccharide (“polysaccharide”) having a positive charge, is provided. The skeletal background of the polysaccharide confers stability to the ligand and its positive charge traps destructive radicals produced during the sterilization process. The molecular weight ratio of sterilization-protecting agent to the ligand should be at least {fraction (1/500)} but less than ½ to protect the ligand effectively without obstructing the ligand's activity. In particular, polysaccharides, such as chitosan (a polymer of D-glucosamine) and chitin which is partially converted into chitosan, are preferable as a sterilization-protecting agent. The biologically active substance in such a material is stabilized against various sterilization methods, including irradiation, wet heat, and chemical sterilization, either in a wet state or a dry state. Further, a method for sterilizing a biologically active substance in the presence of the above-described sterilization-protecting agent is provided.

What is claimed is:  
     
       1. A material comprising 
       a to-be-sterilized material, and  
       a sterilization-protecting agent comprising a trisaccharide or higher saccharide having a positive charge(s),  
       wherein said to-be-sterilized material is a biological acting material comprising  
       a biological acting substance immersed in an aqueous solution which interacts with a biological to-be-affected substance, and  
       a carrier for said biological acting substance.  
     
     
       2. The material according to  claim 1 , wherein said carrier is a porous material and said biological acting substance is held on the surface of said porous material. 
     
     
       3. The material according to  claim 1 , wherein said trisaccharide or higher saccharide has a molecular weight which is at least {fraction (1/500)} but less than ½ of the molecular weight of said biological acting substance. 
     
     
       4. The material according to  claim 1 , wherein said positive charge(s) of said trisaccharide or higher saccharide is owing to an amino group. 
     
     
       5. The material according to  claim 1 , wherein said trisaccharide or higher saccharide comprises a trisaccharide or higher saccharide of glucosamine and/or a derivative thereof. 
     
     
       6. The material according to  claim 5 , wherein said trisaccharide or higher saccharide is chitosan and/or chitin which is partially converted into chitosan. 
     
     
       7. A material comprising a to-be-sterilized material, and 
       a sterilization-protecting agent comprising a trisaccharide or higher saccharide having a positive charge(s),  
       wherein said to-be-sterilized material is a biological acting material comprising  
       a biological acting substance immersed in an aqueous solution which interacts with a biological to-be-affected substance, and a porous material as a carrier for said biological acting substance, and  
       said sterilization-protecting agent is bonded onto the surface of said porous material.  
     
     
       8. The material according to  claim 1 , wherein said biological acting substance is a protein and/or a peptide. 
     
     
       9. The material according to  claim 8 , wherein said biological acting substance is an antibody to a cell surface antigen and/or a peptide having an affinity to the cell surface antigen. 
     
     
       10. The material according to  claim 9 , wherein said antibody is a monoclonal antibody and/or a part thereof. 
     
     
       11. The material according to  claim 9 , wherein said cell is a blood cell. 
     
     
       12. The material according to  claim 8 , wherein said biological acting substance is any member selected from the group consisting of an enzyme, a cytokine and a cell-stimulating factor. 
     
     
       13. The material according to  claim 2 , wherein said porous material is a nonwoven fabric. 
     
     
       14. The material according to  claim 1 , wherein said biological to-be-affected substance is a blood component. 
     
     
       15. A sterilization method for a to-be-sterilized material, which comprises sterilizing said to-be-sterilized material in the presence of a sterilization-protecting agent comprising a trisaccharide or higher saccharide having a positive charge(s), wherein said to-be-sterilized material is a biological acting material comprising a biological acting substance immersed in an aqueous solution which interacts with a biological to-be-affected substance, and a carrier for said biological acting substance. 
     
     
       16. The method according to  claim 15 , wherein said sterilization is conducted in a state that said sterilization-protecting agent is bonded to said to-be-sterilized material. 
     
     
       17. The method according to  claim 15 , wherein said to-be-sterilized material is sterilized in a wet state. 
     
     
       18. The method according to  claim 17 , wherein said sterilization is conducted in a state where said sterilization-protecting agent is allowed to be present in a solution with which said to-be-sterilized material is in contact. 
     
     
       19. The method according to  claim 18 , wherein said sterilization is irradiation sterilization. 
     
     
       20. The method according to  claim 19 , wherein said irradiation sterilization is γ-ray sterilization. 
     
     
       21. The material according to  claim 2 , wherein said positive charge(s) of said trisaccharide or higher saccharide is owing to an amino group. 
     
     
       22. The material according to  claim 3 , wherein said positive charge(s) of said trisaccharide or higher saccharide is owing to an amino group. 
     
     
       23. The material according to  claim 2 , wherein said trisaccharide or higher saccharide comprises a trisaccharide or higher saccharide of glucosamine and/or a derivative thereof. 
     
     
       24. The material according to  claim 3 , wherein said trisaccharide or higher saccharide comprises a trisaccharide or higher saccharide of glucosamine and/or a derivative thereof. 
     
     
       25. The material according to  claim 4 , wherein said trisaccharide or higher saccharide comprises a trisaccharide or higher saccharide of glucosamine and/or a derivative thereof. 
     
     
       26. The material according to  claim 23 , wherein said trisaccharide or higher saccharide is chitosan and/or chitin which is partially converted into chitosan. 
     
     
       27. The material according to  claim 24 , wherein said trisaccharide or higher saccharide is chitosan and/or chitin which is partially converted into chitosan. 
     
     
       28. The material according to  claim 25 , wherein said trisaccharide or higher saccharides is chitosan and/or chitin which is partially converted into chitosan.